US20150281934A1 - Wireless communication system - Google Patents

Abstract

A server control device stores, in a storage device, the correspondence relation between a terminal connected to a base station and an access point that can connect to the terminal instead of the base station, and executes a process for transmitting to the access point a terminal acceptance instruction including information used in determination of the possibility of connection to a terminal at the access point based on the correspondence relation according to sending of an emergency call.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a continuation application of International Application PCT/JP2012/082344 filed on Dec. 13, 2012 and designated the U.S., the entire contents of which are incorporated herein by reference.
FIELD
• The present disclosure relates to a wireless communication system.
BACKGROUND
• By development of a wireless communication network in recent years, many users subscribe a service of acquiring information by communication with a wireless communication network using a mobile terminal (also called a wireless terminal). As examples of the wireless communication network, wireless communication systems according to a wireless communication standard of a cellular network in 3rd Generation Partnership Project (3GPP) like Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UTMS), Wideband Code Division Multiple Access (W-CDMA), Long Term Evolution (LTE), or LTE-Advanced, or wireless communication systems according to a wireless communication standard based on IEEE 802.16e (wireless LAN (Local Area Network)) like wireless fidelity (Wi-Fi) or Worldwide Interoperability for Microwave Access (WiMAX) are spreading.
• A user owns a mobile terminal (a mobile terminal is simply described as a “terminal” hereinafter) according to the wireless communication standard such as a cellular phone (mobile phone), a smartphone, or a wireless LAN terminal, performs communication in a communication area of each wireless communication network, and may obtain information. In recent years, subscribers of a smartphone having both a cellular phone function (a connecting function to a cellular network) and a wireless LAN terminal function (a connecting function to a wireless LAN) are increasing.
• A terminal is usable as a useful tool for promptly acquiring information for recognizing a disaster situation and confirming safety of family members and persons concerned when a disaster such as a typhoon or an earthquake occurs.
• For further information, see Japanese Laid-Open Patent publication No. 2007-258851, Japanese Laid-Open Patent publication No. 2007-143038, Japanese Laid-Open Patent publication No. 2005-39795, Japanese Laid-Open Patent publication No. 2007-74024, Japanese National Publication of International Patent Application No. 2009-521868, Japanese National Publication of international Patent Application No. 2012-503410, Japanese Patent Laid-Open Patent Publication No. 2011-233989, and Japanese Patent Laid-Open Patent Publication No. 2009-267709.
• A situation that many users simultaneously try information communication with a certain event as a trigger is possible to occur. For example, in several hours before and after the end of a year, many users simultaneously try communication of telling a simple greeting. Also, when a disaster such as a typhoon or an earthquake occurs, a situation that many users simultaneously try to acquire information for situation confirmation and safety confirmation is possible to occur. Such access to a cellular network by many users causes congestion of the cellular network. The congestion obstructs early information acquisition by users.
• In a current cellular network, when a congestion state occurs, a process related to communication such as call sending from a terminal is regulated, and the number of the terminals that execute the process is regulated to a predetermined number. Therefore, in the case that the number of the terminals exceeds the predetermined number, there has been a risk that new call sending is not accepted in the cellular network, and users incapable of securing the communication for obtaining safety information arise.
• Also, the decision as to which of a base station for cellular phones and an access point of a wireless LAN a user who owns a smartphone as a terminal connects the terminal to obtain information has been left to the user. The user cannot recognize an arrangement situation (distribution situation) of the base stations and the access points at a current position and a congestion state of each base station and access point. Therefore, the user cannot select a connection destination (one of the base station and the access point) of the terminal with proper assessment of the situation.
SUMMARY
• According to an aspect of the embodiments, a wireless communication system, comprises a base station to which a terminal is connected, an access point of a wireless LAN connected with the terminal instead of the base station when an emergency call is sent, and a server. The base station supplies first information to be used for acceptance by the access point to a terminal connected to the base station according to the sending of the emergency call. The server includes a storage device configured to store a correspondence relation between a terminal connected to the base station and the access point, and a controller configured to execute a process of transmitting to the access point an acceptance instruction of a terminal based on the correspondence relation according to the sending of the emergency call, the acceptance instruction including the first information. The access point performs a connection process with a terminal transmitting the first information, as one of conditions that the first information included in the acceptance instruction is coincident with the first information received from the terminal.
• The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
• It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 illustrates a configuration example of a wireless communication system according to an embodiment;
• FIG. 2 illustrates a configuration example of an access point apparatus (AP) illustrated inFIG. 1;
• FIG. 3 illustrates a configuration example of a server device for disasters (disaster server) illustrated inFIG. 1;
• FIG. 4 illustrates one example of a position registration sequence;
• FIG. 5 illustrates one example of an access point release sequence when a disaster occurs;
• FIG. 6 illustrates one example of the position registration sequence using the access point apparatus;
• FIG. 7 illustrates an example of a sequence (a sequence of transmitting ETWS signals through the AP) when an aftershock occurs or the like;
• FIG. 8 illustrates one example of a safety confirmation sequence (information exchange server utilization sequence) when a disaster occurs;
• FIG. 9 illustrates one example of an AP restoration sequence after a disaster occurs;
• FIG. 10 illustrates a configuration example of a wireless communication system in a second embodiment;
• FIG. 11 is a diagram schematically illustrating the server device for disasters, the access point apparatus and a mobile terminal;
• FIG. 12 illustrates a distribution example ofterminals5;
• FIG. 13A illustrates a stored content example of a position information management database at normal time;
• FIG. 13B illustrates a stored content example of the position information management database when a disaster occurs;
• FIG. 13C illustrates a stored content example of the position information management database at the time of restoration;
• FIG. 14 is a flowchart illustrating details of an access point assignment process;
• FIG. 15A is an explanatory drawing of the access point assignment process;
• FIG. 15B is an explanatory drawing of the access point assignment process;
• FIG. 15C is an explanatory drawing of the access point assignment process;
• FIG. 15D is an explanatory drawing of the access point assignment process;
• FIG. 16 illustrates another example of an assignment state to AP#1-AP#4 of the individual terminals5 (ID “1”-“12”) stored in a positioninformation management DB721 during a fault (failure) of base stations A and B; and
• FIG. 17 illustrates a state when the base station A is restored from a state illustrated inFIG. 16.
DESCRIPTION OF EMBODIMENTS
• Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A configuration of the embodiment is an example, and the present invention is not limited to the configuration of the embodiment.
• For an event of obstructing reservation of communication using a terminal when a disaster occurs, the following factors are conceivable.
• (First Factor)
• When a disaster occurs, it is conceivable that many users simultaneously start communication in the same area. Therefore, in a specific communication infrastructure (for example, a specific base station positioned in the area), it is conceivable that excessive processes for terminals are concentrated and a congestion state occurs. Also, it is possible that the base station undergoes a device failure due to influence of a disaster and falls into a state incapable of connection and communication with the terminals. In this case, it becomes impossible to send signals including ETWS (Earthquake and Tsunami Warning System) signals that are transmitted when an earthquake occurs from the base station to the terminal.
• (Second Factor)
• An existing wireless LAN system does not have a specification or a function of automatically releasing an access point apparatus for free (putting it in a state allowing connection thereto) when a disaster occurs. Also, the system does not have a specification or a function of automatically restoring the above-described release state to an original state (the state of connecting the terminal tentatively connected to the access point apparatus to an original base station apparatus) as needed. Therefore, even if the access point apparatus is released manually or the like, it is not automatically returned to the original state. Thus, as long as the state that the terminal is connected to the access point apparatus is continued, the user of the terminal is not charged. In the case that the access point apparatus is prepared by a carrier (telephone communication provider) of a cellular network, burdens on the carrier become huge.
• (Third Factor)
• In wireless LAN communications, a wireless LAN terminal downloads or uploads data having a large size like image data or video data from/to an IP (Internet Protocol) network (for example, the Internet) in many cases. In particular, many applications of a smartphone are GUI-based ones, and a large capacity of data is transmitted and received when executing the applications. Under an environment of such wireless LAN communication of transmitting and receiving a large amount of the data in a large size, there is a risk that the communication for safety confirmation in a disaster is obstructed.
• In the embodiment, in consideration of the first factor, a state that access of terminals is concentrated at a specific communication infrastructure (a base station, for example) is avoided, and an operation for leveling is performed. Therefore, in the embodiment, a terminal connectable to both a cellular network (carrier network) and a wireless LAN (which is one example of other wireless communication networks) is applied. That is, the terminal has a function capable of switching a connection destination between a base station apparatus and an access point apparatus (sometimes described as an “access point”, hereinafter) of a wireless LAN.
• A terminal connected to the base station of the cellular network reports position information of the terminal itself (user) to a management server device (sometimes described as a “management server”, hereinafter) of a carrier network through the base station. The management server of the carrier network transmits the reported position information of the terminal to a server device for disasters (sometimes described as a “server for disasters” or a “disaster server”, hereinafter). The access point of the wireless LAN includes an interface capable of communicating with the management server and the server for disasters in an emergency including the time of a disaster.
• The server for disasters has a function of recognizing one or more access points used for distributing loads by changeover from the carrier network to the wireless LAN beforehand based on the position information of the terminal. The management server is capable of converting the position information of the terminal connected to the carrier network from a format managed in the carrier network to a format for management in the server for disasters, and transmitting it to the server for disasters. By providing the server for disasters with such processed position information of the terminal, process loads of the server for disasters may be reduced, and disaster resistance may be improved. The server for disasters may determine assignment of users to one or more access points used for load distribution based on the position information of the terminal provided from the management server.
• The server for disasters recognizes a distribution of the access points and the users (terminals) (the correspondence relation between the access points and the terminals) beforehand, from the position information. Thereafter, when a notice (ETWS (Earthquake and Tsunami Warning System) information) of disaster occurrence is generated, a base station apparatus (sometimes described as a “base station”, hereinafter) of the carrier network receives signals including the ETWS information, and transmits (broadcasts) an SSID (Service Set Identifier) for AP release to trigger the terminal to switch from the base station to the access point to individual subordinate terminals. The terminal tries the connection to the access point (generates a line establishment request) using the SSID for the AP release. The SSID for the AP release is one example of “first information”, “information used for determining the propriety of the connection with the terminal”, and “information included in a connection request”, and the ETWS information (emergency information) is one example of “second information”.
• The access point shifts to an attitude of receiving the terminal that has received the SSID for the AP release under control of the server for disasters. That is, the server for disasters, when receiving an instruction to send the SSID for the AP release from the management server, notifies the access point of adjacent terminals to be accommodated by the access point based on the correspondence relation between the terminals connected to the base station and the access points. Receiving the notice, the access point receives the line establishment request of the terminal using the SSID for the AP release and connects the terminal. The terminal connected to the access point leaves the base station. In this way, an accommodating situation of the users in the base station and the access point may be controlled from a carrier network side. Further, in the above-described operation, by controlling the correspondence relation between the terminals and the access points to connect the terminals, the numbers of the users (terminals) to the individual access points are distributed, and the state that the terminals are concentrated at one base station and one access point is avoided.
• Also, in the embodiment, in consideration of the second factor, means for releasing/restoring the base station apparatus/access point in an area where a problem is generated by a disaster is provided. By simultaneously monitoring the state of the base station and the state of the wireless LAN, even for restoration after a disaster, by restoring the individual access points in order, automatically stabled restoration means may be provided.
• In the case that there is a failure (device failure, link failure) of the base station due to disaster occurrence, the terminals connected to the base station are accommodated in a nearby access point. The terminals accommodated in the access point are returned to the state of being connected to the base station in a predetermined order with the restoration of the base station from a failure state as a trigger. At the time, depending on a restoration situation on a base station side, the target access point for returning the terminals to the state of being connected to the base station may be selected. Charging may be started from the terminal returned to a normal operation.
• Also, in the embodiment, in consideration of the third factor, means for executing safety confirmation by a relatively small amount of data communication in a disaster is provided. That is, in the embodiment, the server for disasters has its own Web server function. When a disaster occurs, the access point (AP) for example is controlled so as to be connected to the server's own Web server alone. Thus, an amount of the data communication may be reduced as much as possible. Also, from the position information acquired in the server for disasters, the position information of the user written onto the Web server may be notified to a specific user. Hereinafter, the wireless communication system according to the embodiment will be described further in detail.
First EmbodimentSystem Configuration Example
• FIG. 1 illustrates a configuration example of the wireless communication system according to the embodiment.FIG. 1 illustrates an example that a 3G system (UMTS) is applied as a wireless communication network (cellular network: carrier network) for cellular phones. However, the cellular networks based on other communication standards like GSM, LTE, or LTE-Advanced may be applied. Also, while an example that Wi-Fi is applied as the wireless LAN is illustrated, other wireless communication standards (WiMAX, for example) may be also applied.
• InFIG. 1, the wireless communication system roughly includes a PSAP (Public Safety Answering Point: emergency answering organization), a cellular network (carrier network)1A, awireless LAN1B, an IP (Internet Protocol) network (for example, the Internet)8, and a server device for disasters (disaster server)7. Abase station controller3 and abase station apparatus4 included in thecellular network1A, aterminal5, acarrier management apparatus6, thedisaster server7, a provider (provider device)9, and anaccess point apparatus10 each has an intrinsic address, and may communicate using the address.
• <<PSAP>>
• ThePSAP1 sends an emergency call in an emergency such as a disaster or an accident. The emergency call includes the ETWS (Earthquake and Tsunami Warning System) information (emergency information) for reporting an earthquake/tsunami warning. The ETWS information has a predetermined format. ThePSAP1 may send the emergency call including the ETWS information by a predetermined ETWSsignal sending function11. ThePSAP1 is connected to acore network2 of thecellular network1A and thedisaster server7 through a communication line, and ETWS signals are transmitted to thecore network2 and thedisaster server7.
• <<Cellular Network>>
• The cellular network includes thecore network2, the base station controller (called a Radio Network Controller: RNC)3, and the base station apparatus (called a base station, BTS or Node B (NB))4, and thecarrier management apparatus6.
• Thecore network2 has a connecting function to other backbone networks such as the Internet or an ISDN network, and a connecting function with a mobile phone network and a fixed phone network or the like. Thecore network2 includes one or more core network apparatuses (core NW apparatuses)21 of SIN (Signaling Interworking Node for 3G access) or xGSN (serving/gateway General packet radio service Support Node) or the like. Thecore network apparatus21 includes an interface circuit for being connected with an IP-compliant base station controller3 (IP-RNC) through a communication line, and an interface circuit for receiving the ETWS signals from thePSAP1. Also, for thecore network apparatus21, for example, an existing core network apparatus based on a predetermined communication standard like 3GPP may be applied.
• Thebase station controller3 is a controller that organizes thebase station4. Thebase station controller3 has a3GPP protocol function31. The3GPP protocol function31 is a 3GPP-based interface for performing communication between thebase station controller3 and each node (for example, thebase station4, the carrier management apparatus6), and is realized by an interface circuit for being connected with thebase station4 and thecarrier management apparatus6 through a communication line. Also, for thebase station controller3, an existing base station controller based on a predetermined communication standard like 3GPP may be applied.
• Thebase station4 is an IP-compliant base station (IP-BTS), forms an area (cell) where theterminal5 is wirelessly connected, and performs wireless communication with the terminal. Thebase station4 has awireless communication function41 and a3GPP protocol function42.
• Thewireless communication function41 performs the wireless communication with theterminal5. For example, thewireless communication function41 transmits and receives radio signals including position information based on 3GPP. The3GPP protocol function42 is a 3GPP-based interface for communicating with thebase station controller3, and is realized by an interface circuit for being connected with thebase station controller3 through a communication line. Also, for thebase station4, an existing base station apparatus based on a predetermined communication standard like 3GPP may be applied.
• Also, while onebase station controller3 and onebase station4 are illustrated inFIG. 1, actually, the plurality ofbase station controllers3 and the plurality ofbase stations4 each having the above-described functions are installed.
• As theterminal5, the terminal (for example, a smartphone, a feature phone, or a PDA) having both a function (cellular phone (UE) function) as a connecting terminal (called User Equipment (UE)) to thecellular network1A and a wireless LAN terminal function is applied. Theterminal5 has awireless communication function51. Thewireless communication function51 includes a function of being selectively connectable to thecellular network1A and thewireless LAN1B, and a function of transmitting and receiving signals including the position information based on 3GPP and performing wireless LAN communication.
• Theterminal5 performs the wireless communication with thebase station4 when connected to thecellular network1A (base station4). For example, theterminal5 includes a UE function module for transmitting and receiving the radio signals including the position information based on 3GPP to/from thebase station4. Also, theterminal5 includes a wireless LAN connection module (wireless LAN terminal function module) for performing a connection process with theaccess point apparatus10 and performing the wireless communication including data when connected to the wireless LAN. Theterminal5 also performs authentication using the SSID or the like when connected to the wireless LAN. Also, the functions of theterminal5 are the functions that an existing smartphone or feature phone or the like has, and the existing smartphone or feature phone or the like may be applied.
• In the embodiment, theterminal5 receives ETWS Paging signals including the SSID for the AP release from thebase station4. Theterminal5 further includes a function of, in the case that the ETWS Paging signals including the SSID for the AP release are received, turning ON the wireless LAN connection module if it is in an OFF state and executing the wireless LAN connection using the SSID included in the ETWS Paging signals.
• When trying the wireless LAN connection, theterminal5 receives surrounding radio waves, and confirms whether or not the connection is possible with the access point which is a source of the received radio waves. Upon the confirmation, theterminal5 also checks a security level or the like. In a confirmation process, when the SSID requested by the access point is unknown, the connection is denied by security.
• Theterminal5 which has received the ETWS Paging signals checks the SSID for the AP release included in the ETWS Paging signals, and searches the access point connectable by the SSID for the AP release. Thus, theterminal5 may be connected with the access point that gives a permission to access (connection request: line establishment request) from theterminal5 using the SSID for the release. Theterminal5 that is connected with the access point may transmit and receive information to/from the access point on condition that an intrinsic identifier (terminal ID) that theterminal5 has and a terminal ID that the access point has coincide. In the embodiment, to the access point, the terminal ID is supplied from the server for disasters.
• The carrier management apparatus (cellular network management apparatus)6 is a server that manages thecellular network1A, and may be achieved by application of an exclusive or general-purpose computer (information processor) and an exclusive or general-purpose server machine. Thecarrier management apparatus6 includes a3GPP protocol function61, aposition information manager62, and an IP-IF (IP network interface)controller64.
• The3GPP protocol function61 is a 3GPP-based interface for communicating with thebase station controller3, and is realized by an interface circuit connected with thecore network apparatus21 of thecore network2 through a communication line.
• Theposition information manager62 manages the position information of theterminal5 connected to thecellular network1A (base station4) using a position information management database (position information management DB)63. The positioninformation management DB63 is a database (DB) that stores the position information of theterminal5. The position information may include, in addition to the position information of theterminal5, information of thebase station4 to which theterminal5 is connected for example. The IP-IF controller64 is an IP interface (LAN chip, LAN card) having an interface circuit for being connected to the IP network (the Internet)8.
• Thedisaster server7 is achieved using an exclusive or general-purpose computer (personal computer (PC), work station (ST) or the like). Thedisaster server7 includes aWeb function71, aposition information manager72, acontroller73 that performs an ETWS process (release, restoration control) and AP assignment control, and an IP-IF controller74.
• TheWeb function71 has a GUI (Graphical User Interface) engine and a CUI (Character User Interface) engine, and uses a Web database (Web DB)711 to perform its own Web management (support of an information exchange service (for example, a bulletin board system (BBS), Twitter®)) that is applied when a disaster occurs. TheWeb DB711 is a database that stores data and information for theWeb function71 to perform the Web management.
• In theWeb DB711, data for GUI (graphical user interface) and CUI (character user interface) display (data for UI display) is stored. The data for the UI display is provided for (downloaded to) theterminal5 to utilize the bulletin board system or Twitter provided for theterminal5 when a disaster occurs. The data for the UI display is the data for display for which an amount of data is reduced as much as possible compared to normal UI by being created on a text basis for example.
• Theposition information manager72 manages the position information of theterminal5 received from thecarrier management apparatus6. That is, theposition information manager72 stores the position information of theterminal5 received from thecarrier management apparatus6 in a positioninformation management DB721, and manages theterminal5 using the position information.
• Also, theposition information manager72 manages information of theterminal5 whose connection destination is switched from thecellular network1A to thewireless LAN1B in a disaster and information of the connectedaccess point10, using an access point (AP)information DB722. TheAP information DB722 may store a correspondence relation between the information (AP information) of theaccess point10 switchable from thebase station4 in a disaster and theterminal5 connected to theaccess point10 by a switching process. The information of theterminal5 includes the terminal ID which is intrinsic identification information of theterminal5. The AP information includes the SSID for the AP release to be used to accept theterminal5 by theaccess point10 whose utilization is released (which may be utilized without a charge) in a disaster or the like.
• For the SSID for the AP release, a configuration of being statically stored in a storage device (for example, aflash ROM734,FIG. 3) that thedisaster server7 has may be adopted. Or, a configuration that thedisaster server7 receives the SSID for the AP release transmitted from thecore network apparatus21 through thecarrier management apparatus6 may be also adopted.
• For example, in the case that thecore network apparatus21 transmits the SSID for the AP release to thebase station controller3, information (base station ID) of eachbase station4 accommodated by thebase station controller3 and the SSID for the AP release are associated and sent to thecarrier management apparatus6. Thecarrier management apparatus6 sends the SSID for the AP release and the base station ID through theIP network8 to thedisaster server7.
• In thedisaster server7, for example, in the positioninformation management DB721, the correspondence relation between thebase station4 and the AP10 (the base station ID and an ID (AP-ID)) of theAP10 is stored in correspondence. The disaster server7 (for example, theposition information manager72 or the controller73) which has received the SSID for the AP release and the base station ID stores the SSID for the AP release corresponding to the base station ID and the AP-ID in the positioninformation management DB721. The SSID for the AP release is used when releasing the AP.
• Thecontroller73 performs a process of assigning theterminal5 connected to thebase station4 to aproper access point10 based on the position information of theterminal5 stored in the positioninformation management DB721. Also, thecontroller73 instructs a release process and restoration (release state cancellation) of theaccess point10 in a disaster. Further, thecontroller73 processes the ETWS information that reaches thedisaster server7 through thePSAP1 or thewireless LAN1B.
• The IP-IF controller74 is an IP interface (LAN chip, LAN card) having an interface circuit for being connected to theIP network8. Thedisaster server7 is connected with thecarrier management apparatus6, the provider device (provider)9, and theaccess point10 through theIP network8. Thus, thedisaster server7 may receive the position information from thecarrier management apparatus6, and accept the access to the Web function71 (bulletin board system, Twitter) from theaccess point10.
• Theprovider9 is a device of a vendor accommodating theaccess point10, and operates theaccess point10 by performing access point (AP)control91.
• The access point apparatus10 (described as “AP10”, hereinafter) forms thewireless LAN1B, and may accommodate theterminal5 through the connection process. While oneAP10 is illustrated inFIG. 1, actually, two ormore APs10 may be arranged inside a communication area (cell) of thebase station4 or near the cell. TheAP10 is arranged at HOTSPOT®, for example.
• TheAP10 includes a release/restoration manager101, an ETWSinformation transmission function102, awireless communication function103, and an IP-IF controller104. The release/restoration manager101 performs control of theterminal5 which is an accommodation target terminal of theAP10 when a disaster occurs, and force-out control of theterminal5 which is the accommodation target terminal when performing restoration (when canceling a release state). Further, the release/restoration manager101 may transmit the ETWS signals through theAP10 when releasing theAP10.
• The ETWSinformation transmission function102 transmits the ETWS information through theAP10. Thewireless communication function103 is a wireless interface including an interface circuit that performs transmission and reception of signals including the position information based on 3GPP and the wireless LAN communication.
• The functions or the processes provided in thePSAP1, thecore network apparatus21, thebase station controller3, thebase station4, thecarrier management apparatus6 and theterminal5 illustrated inFIG. 1 may be achieved, for example, by a hardware configuration using an exclusive or general-purpose electric/electronic circuit (for example, an integrated circuit like an IC, an LSI, or an ASIC). Or, some of the functions or the processes may be achieved by, in a processor configuration including a processor (for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor)), an auxiliary storage device and a main storage device, the processor loading a program stored in the auxiliary storage device onto the main storage device and executing it. Some of the functions or the processes may be also achieved by a programmable logic device (PLD) like an FPGA (Field Programmable Gate Array) or a CPLD (Complex Programmable Logic Device). Further, the functions or the processes may be achieved by a combination using at least two of the hardware configuration, the processor configuration, and the PLD described above.
• Also, the positioninformation management DB63 illustrated inFIG. 1 is created on a storage area of a storage device (storage) that thecarrier management apparatus6 has. Also, theWeb DB711, the positioninformation management DB721, and theAP information DB722 that thedisaster server7 has are created on a storage area of a storage device (storage) that thedisaster server7 has.
• <<Access Point Apparatus>>
• FIG. 2 illustrates a configuration example of the access point apparatus10 (AP10) illustrated inFIG. 1. InFIG. 2, theAP10 includes aCPU111, anSDRAM112, and aflash ROM113 interconnected through a bus B1. Also, theAP10 includes awireless module115 and the IP-IF controller104 connected with theCPU111 through a bus B2, and anantenna114 is connected to thewireless module115.
• TheCPU111 is one example of a processor or a controller, theSDRAM112 is one example of a main storage device (storage device), and theflash ROM113 is one example of an auxiliary storage device (storage device). By loading a program stored in theflash ROM113 onto theSDRAM112 and executing it, theCPU111 functions as the above-described release/restoration manager101, and may achieve the ETWSinformation transmission function102.
• Theantenna114 and thewireless module115 achieve the above-describedwireless communication function103. Thewireless module115 is formed by an electric/electronic circuit group forming a down converter and an up converter between an RF (radio frequency) and an IF (intermediate frequency), a signal amplifier, an analog-digital converter, and a digital-analog converter. For example, by thewireless module115, a generation process of baseband signals and a demodulation process and a decoding process of the baseband signals are performed, and user data from theterminal5 may be obtained. TheCPU111 generates, for example, an IP packet including the user data. The IP-IF controller104 generates a LAN frame including the IP packet received from theCPU111, and sends it out to theIP network8.
• <<Disaster Server>>
• FIG. 3 illustrates a configuration example of thedisaster server7 illustrated inFIG. 1. Thedisaster server7 illustrated inFIG. 3 has a hardware configuration in the case of utilizing hardware architecture of a PC. InFIG. 3, thedisaster server7 includes anSDRAM732, an input/output port733, the IP-IF controller74, and theflash ROM734 that are connected with aCPU731 through a bus B3.
• Further, thedisaster server7 includes anSDRAM735, a storage (storage device)711A storing theWeb DB711, a storage (storage device)721A storing the positioninformation management DB721, and a storage (storage device)722A storing theAP information DB722 that are interconnected with theCPU731 through a bus B4.
• TheCPU731 is one example of a processor (controller), theSDRAMs732 and735 are examples of a main storage device, and theflash ROM734 and thestorages711A,721A and722A are examples of an auxiliary storage device. Also, instead of theSDRAMs732 and735, one SDRAM may be applied. Also, instead of thestorages711A,721A and722A, one or two storages may be applied as well.
• TheCPU731 functions as thecontroller73 that performs the ETWS process and the AP assignment control by loading a program stored in theflash ROM734 onto theSDRAM732 and executing it, for example. The input/output port733 is connected to thePSAP1 through a communication line, and may receive the ETWS signals from thePSAP1 and supply them to theCPU731. TheCPU731 performs the ETWS process using the ETWS signals.
• Also, the IP-IF controller74 is connected to theIP network8 through a communication line, and for example, receives the position information of the terminal5 from thecarrier management apparatus6 and supplies it to theCPU731. TheCPU731 registers the position information to the positioninformation management DB721A by functioning as theposition information manager72. Also, theCPU731 executes an AP assignment process using the position information of theterminal5 stored in the positioninformation management DB721A and the AP information stored in theAP information DB722. Further, theCPU731 may, in response to an access request for the bulletin board system or Twitter from theterminal5 received by the IP-IF controller74, read the data for the UI display stored in theWeb DB711, generate a packet including the data for the UI display, and transmit it to theterminal5 through the IP-IF controller74.
• <Operation Sequence of Wireless Communication System>
• In the above-described wireless communication system, roughly, the following six operation sequences are performed. Hereinafter, examples of the individual operation sequences will be described.
• (1) Position registration sequence
• (2) Access point release sequence upon disaster occurrence
• (3) Position registration sequence (access point)
• (4) Sequence upon aftershock
• (5) Safety confirmation sequence upon disaster occurrence
• (6) Access point restoration sequence after disaster occurrence
• <<(1) Position Registration Sequence>>
• FIG. 4 illustrates one example of the position registration sequence. Broken line arrows inFIG. 4 indicate 3GPP communication (cellular network communication), and solid line arrows indicate IP packet communication or internal communication of each apparatus. InFIG. 4, theterminal5 connected to thebase station4 acquires the position information of the terminal5 (FIG.4<1>). The acquired position information is transmitted to thebase station4 by Measurement signals by the wireless communication function51 (FIG.4<2>).
• The position information is received by thewireless communication function41 of thebase station4, and transmitted to thebase station controller3 by the 3GPP protocol function42 (FIG.4<3>). Thebase station controller3 sends the position information to the core network2 (core network apparatus21) by the 3GPP protocol function31 (FIG.4<4>). Thecore network apparatus21 transmits the position information to the carrier management apparatus6 (FIG.4<5>). In thecarrier management apparatus6, theposition information manager62 registers the position information to the positioninformation management DB63. Theposition information manager62 converts (processes) the position information registered in the positioninformation management DB63 to a format for transmission to thedisaster server7, and sends it to thedisaster server7 as position information data (FIG.4<6>). The position information data includes identification information (terminal ID) of theterminal5 connected to thebase station4. In thedisaster server7, theposition information manager72 stores the position information data in the positioninformation management DB721. The position information data is delivered to theposition information manager72, and registered to the position information management DB721 (FIG.4<7>).
• As indicated in the above-described position registration sequence, in the wireless communication system of the embodiment, the position information of the terminal5 (UE) is collected by the Measurement signals and managed in the positioninformation management DB63 before disaster occurrence. The position information is also registered to the positioninformation management DB721 inside thedisaster server7. Inside thedisaster server7, as the AP assignment control by thecontroller73, mapping of theterminal5 based on the position information is performed. That is, thecontroller73, as the mapping, associates theterminal5 and theAP10 to be an assignment destination (allocation destination) for the time of a disaster (calculates allocation prediction), using the position information of theAP10 of thewireless LAN1B registered beforehand in theAP information DB722. A result of the mapping (allocation prediction) is registered to the positioninformation management DB721.
• The mapping is executed for eachbase station4. The mapping may be executed with all theterminals5 connected to onebase station4 as targets. It is because that there is a possibility that thebase station4 becomes incapable of maintaining a proper connection state with thesubordinate terminals5 due to the device failure or link failure of thebase station4 by a disaster.
• Of course, for example, in the case that the possibility that thebase station4 falls into a failure state in a disaster is low, distributing loads between thebase station4 and one ormore APs10 is conceivable. In this case, for example, the number of theterminals5 to maintain the connection with thebase station4 regardless of the release of theAP10 may be determined as a threshold, and the mapping may be executed to theterminals5 exceeding the threshold among theterminals5 connected to onebase station4.
• An upper limit may be determined for the number of theterminals5 to be accepted by oneAP10 when a disaster occurs. The upper limit may be determined in consideration of radio resources to be utilized by theterminals5 and buffer resources for data transfer, for example. In this case, the plurality ofterminals5 are associated with one, two ormore APs10 so as not to exceed the determined upper limit, in the mapping. In this way, the loads may be distributed among the plurality ofAPs10. Also, as described later, theterminal5 switched to theAP10 is turned to a state capable of text-basis communication for obtaining information related to a disaster alone. Therefore, the upper limit of a resource amount to be allocated to oneterminal5 may be assumed, and the upper limit may be easily determined.
• Also, the above-described position registration sequence is performed at least in the case that theterminal5 is newly connected to thebase station4. Also, in the case that theterminal5 leaves the cell of the base station4 (disconnects the connection with the base station4), the information of theterminal5 is deleted from the positioninformation management DB63 of thecarrier management apparatus6, the information of theterminal5 is deleted also from the positioninformation management DB721 of thedisaster server7, and the mapping (correspondence) of theterminal5 and theAP10 is updated.
• <<(2) Access Point Release Sequence Upon Disaster Occurrence>>
• FIG. 5 illustrates one example of the access point release sequence upon disaster occurrence. By disaster (earthquake, for example) occurrence, an emergency call is sent from thePSAP1 to the core network apparatus21 (FIG.5<1A>). The emergency call is also transmitted to the disaster server7 (FIG.5<1B>).
• In thedisaster server7, thecontroller73 generates a message of an instruction to release theAP10. The AP release instruction is transmitted through theIP network8 to theAP10 and the provider9 (FIG.5<3>). When receiving the AP release instruction, the provider9 (provider device) is turned to a state of not executing a charging process for the utilization of theAP10 using the SSID for the release.
• Theprovider9 performs the following process asAP control91. That is, theprovider9 includes a charging server that performs the charging process to the terminal utilizing the wireless LAN. The provider9 (charging server) receives the information (for example, the SSID and the terminal ID) of the terminal (user) connected with theAP10 from thedisaster server7 or theAP10 through theIP network8, and performs charging (integration of charges).
• In the embodiment, theprovider9 receives the AP release instruction from thedisaster server7 through theIP network8. The AP release instruction includes the SSID for the AP release, and the terminal ID of theterminal5 capable of utilizing theaccess point10 using the SSID for the AP release. Theprovider9 which has received the AP release instruction temporarily stops charging for wireless LAN utilization of the terminal (terminal ID) using the SSID for the release.
• Specifically, the provider9 (charging server) receives, as user information related to charging, the SSID, the terminal ID, and charging information (for example, a packet amount). Then, theprovider9 determines whether or not the SSID and the terminal ID included in the user information coincide with the SSID for the AP release and the terminal ID acquired by the reception of the AP release instruction. In the case that the SSID and the terminal ID coincide, theprovider9 does not perform the charging process to the terminal5 (user) having the terminal ID. Thus, during the AP release, theterminal5 that utilizes the wireless LAN using the SSID for the AP release may utilize the wireless LAN for free.
• In contrast, in the case of receiving an AP restoration instruction including the SSID for the release and the terminal ID and a release SSID invalidation notice (FIG. 9), theprovider9 restarts charging to the terminal5 (user) specified by the SSID for the AP release and the terminal ID. The AP restoration instruction is transmitted from thedisaster server7 through theIP network8 to theprovider9.
• Also, regarding the provider9 (charging server), instead of the above-described configuration, the following configuration may be adopted. For example, the configuration of notifying the SSID for the release alone from thedisaster server7 to theprovider9 may be applied. In this case, theprovider9 determines coincidence/non-coincidence of the SSID in the user information received from theAP10 and the SSID for the release. When the SSIDs coincides, theprovider9 does not perform (avoids) the charging process to the terminal5 (user) having the terminal ID in the user information.
• Or, the configuration of not transmitting the AP release instruction from thedisaster server7 to theprovider9 may be applied as well. In this case, theprovider9 stores the SSID for the AP release on the storage device beforehand. When receiving the user information related to charging from theAP10, theprovider9 determines whether or not the SSID in the user information and the SSID for the AP release coincide. In the case that both coincide, theprovider9 avoids the charging process related to the terminal ID in the user information.
• On the other hand, in theAP10 which has received the AP release instruction, the release/restoration manager101 shifts theAP10 to an AP release mode (FIG.5<4>).
• Incidentally, thecore network apparatus21 which has received the emergency call stores the SSID for the AP release on the storage device provided in itself, and transmits ETWS WriteReplace signals including the SSID for the release and the emergency information (ETWS information) included in the emergency call to the base station controller3 (FIG.5<5>). Thebase station controller3 transmits the ETWS Paging signals on which the SSID for the AP release and ETWS indication information (etws-indication) are superimposed to the base station4 (FIG.5<6>). Also, in the embodiment, thecore network apparatus21 holds the SSID for the AP release beforehand, however, the configuration of storing the SSID for the AP release beforehand by thebase station controller3 or thebase station4 and including it in the ETWS Paging signals may be adopted. As described later, as the SSID for the AP release, one of an SSID (common ID) that is common among the APs and an intrinsic SSID (intrinsic ID) may be applied. In the case that the common ID is applied, by providing it in a device (for example, the core network apparatus21) on an upstream side of a transmission route of the ETWS information, troublesomeness of providing the identical common ID in individual downstream side devices may be avoided.
• Thebase station4 transmits, to thesubordinate terminals5, the ETWS Paging signals on which the SSID for the AP release and the ETWS indication information (etws-indication) are superimposed (FIG.5<6A>). Theterminal5 may receive the ETWS Paging signals on which the SSID for the AP release and the ETWS indication information (etws-indication) are superimposed from thebase station4, and acquire (receive) the SSID for the AP release (FIG.5<6B>).
• To the “ETWS-Paging signals”, the SSID for the AP release and the ETWS indication information (etws-Indication) are imparted. Theterminal5 tries to receive the paging signals intermittently in a predetermined cycle (on a 3GPP specification, 320 msec, 640 msec, 1.28 msec, 2.56 msec or the like may be set for example).
• Theterminal5 based on the 3GPP specification starts receiving reporting information including the emergency information (ETWS information (ETWS primary notification, ETWS secondary notification)) in the case of detecting the Paging signals (ETWS-Paging) to which “etws-Indication” is imparted.
• According to the 3GPP specification, the first emergency information “ETWS primary notification” is transmitted using reporting information of an SIB 10 (System Information Block Type 10), and the second emergency information “ETWS secondary notification” is transmitted using reporting information of an SIB 11 (System Information Block Type 11) from thebase station4. The ETWS information received from thecore network apparatus21 in thebase station controller3 is transmitted to thebase station4, and thebase station4 provides the terminal5 with the ETWS information using the above-described reporting information.
• Also, theterminal5 based on the 3GPP specification may execute a reporting process of sounding an alarm or the like when detecting the Paging signals to which “etws-Indication” is imparted.
• Instead of the above-described configuration, thebase station controller3 may transmit the ETWS-Paging signals including the ETWS information received from thecore network apparatus21 further in addition to the SSID for the AP release and the ETWS indication information (etws-Indication) as the ETWS signals to thebase station4. In this case, thebase station4 transmits the ETWS signals to theterminal5, and theterminal5 acquires the SSID for the release and the ETWS information from the ETWS signals. In this case, a timing at which theterminal5 acquires the ETWS information may be advanced.
• In the 3GPP specification, the ETWS information (etws-information) in the ETWS-Paging signals is optional information (additional information). By detecting (recognizing) the additional information in the ETWS-Paging signals, theterminal5 may acquire the ETWS information (may distinguish normal Paging signals from the Paging signals including the ETWS information). In the configuration, compared to the case of acquiring the ETWS information from the reporting information, theterminal5 is expected to acquire the ETWS information in an early stage.
• When receiving the SSID for the AP release from thebase station4, theterminal5 is turned to a state of transmitting the line establishment request including the SSID for the AP release and the terminal ID of theterminal5 itself to theAP10.
• Here, for the SSID for the AP release, an intrinsic value (intrinsic ID) for each AP may be applied, and a value (common ID) which is common among all the APs to be released may be applied. In the case that the intrinsic ID is used, theterminal5 transmits a request of connection establishment just to therelevant AP10 using the intrinsic ID allocated to itself. Therefore, eachAP10 may avoid receiving the request of the connection establishment from unrelated terminals. In other words, theAP10 may effectively avoid the possibility of generating congestion by processes to the connection establishment requests from many unrelated terminals (a decoding process to the connection establishment request, a transmission process of a denial response, or the like).
• In the case that the common ID is used, eachAP10 compares the terminal ID (the ID of theterminal5 itself) included in the connection establishment request with the terminal ID included in an acceptance instruction received beforehand, and establishes the connection in the case that the terminal IDs coincide. On the contrary, in the case that the terminal IDs do not coincide, the connection of theterminal5 and theAP10 is not established. In this way, eachAP10 may avoid the connection establishment with unrelated terminals to which the connection is not allocated.
• Also, in the case that the intrinsic ID is used, in an LTE communication system for example, the intrinsic ID of the AP allocated to each terminal is set as an information element subordinate to PagingRecord information which is an information element of Paging information stipulated by 3GPP TS36.331 Sec6.2.2. In contrast, in the case that the common ID is used, in the LTE communication system for example, the common ID is set as an information element immediately under the Paging information stipulated by 3GPP TS36.331 Sec6.2.2.
• A specific example of a Paging information element in the case that the intrinsic ID is used and a specific example of the Paging information element in the case that the common ID is used are indicated below. In the following specific examples, various kinds of information related to an authentication system, an encryption system and an authentication key or the like may be acquired from eachAP10 beforehand and stored and managed corresponding to each AP, or may be a common value. Also, the various kinds of information on the authentication system, the encryption system and the authentication key indicated in the following examples may be also included together with the SSID for the release in the acceptance instruction to the AP described above, and transmitted to each AP.

• 	TABLE 1
  	(A content example using an intrinsic ID)

  Paging ::=

  SEQUENCE {

  pagingRecordList

  PagingRecordList

  OPTIONAL,

  -- Need ON

  systemInfoModification

  ENUMERATED {true}

  OPTIONAL,

  -- Need

  ON

  etws-Indication

  ENUMERATED {true}

  OPTIONAL,

  -- Need ON

  nonCriticalExtension SEQUENCE { }

  OPTIONAL

  -- Need OP

  }

  PagingRecordList ::= SEQUENCE (SIZE (1..maxPageRec)) OF PagingRecord

  PagingRecord ::=

  SEQUENCE {

  	ue-Identity	PagingUE-Identity.
  	on-Domain	ENUMERATED {ps, cs}.

  	SSID of AP (intrinsic ID) : character strings having a given length
  	Authentication method of AP : WPA-PSK, WPA2-PSK and etc.
  	Encryption method of AP : TKIP, AES and etc.
  	Authentication key of AP : Authentication key having a given length such

  as 64bit, 128bit and etc.

  ...

  	}

• 	TABLE 2
  	(A content example using a common ID)

  Paging ::=

  SEQUENCE {

  pagingRecordList

  PagingRecordList

  OPTIONAL,

  -- Need ON

  systemInfoModification

  ENUMERATED {true}

  OPTIONAL,

  -- Need

  ON

  etws-Indication

  ENUMERATED {true}

  OPTIONAL,

  -- Need ON

  nonCriticalExtension SEQUENCE { }

  OPTIONAL

  -- Need OP

  	SSID of AP (common ID) : character strings having a given length
  	Authentication method of AP : WPA-PSK, WPA2-PSK and etc.

  	Encryption method of AP : TKIP, AES and etc.
  	Authentication key of AP : Authentication key having a given length such

  as 64bit, 128bit and etc.

  	}

• Incidentally, thecontroller73 of thedisaster server7 which has received the emergency call requests AP position/terminal position information to the position information manager72 (FIG.5<7>). Theposition information manager72 returns an AP position/terminal position information response including a mapping result (the correspondence relation between theAP10 and the terminal5) and an address of a transmission destination of a terminal acceptance instruction (the address of theAP10 to be a destination) to the controller73 (FIG.5<8>).
• Thecontroller73 generates a terminal acceptance instruction message for instructing acceptance of theterminal5 to theAP10 using the correspondence relation between theAP10 and theterminal5 included in the AP position/terminal position information response, and transmits it to the AP10 (FIG.5<9>). The terminal acceptance instruction message includes, at least, the SSID for the AP release (the common ID or the intrinsic ID), and the terminal ID of at least oneterminal5 that may be accepted. The terminal acceptance instruction message is one example of the acceptance instruction. The SSID for the AP release may be stored in the storage device (for example, the flash ROM734) beforehand. Or, thedisaster server7 may receive it from thecore network apparatus21 through thecarrier management apparatus6.
• Here, for the terminal acceptance instruction, one of transmission (unicast) for which the address of apredetermined AP10 is a destination and transmission (multicast) for which a group (multicast group) ofdestination APs10 is specified may be applied.
• In the case that the unicast is applied, thecontroller73 transmits the terminal acceptance instruction including the SSID for the AP release (the common ID or the intrinsic ID) and the terminal ID of at least oneterminal5 that may be accepted, specifying the address of thedestination AP10. Thedestination AP10 performs an acceptance process of theterminal5 using the SSID for the AP release and the at least one terminal ID included in the terminal acceptance instruction which has arrived in itself.
• In the case that the multicast is applied, thecontroller73 transmits the terminal acceptance instruction including the SSID for the AP release (the common ID or the intrinsic ID) and the terminal ID of at least oneterminal5 that may be accepted, specifying a multicast address of the multicast group to which the plurality ofpredetermined APs10 belong. TheAP10 belonging to the multicast group performs the acceptance process of theterminal5 using the SSID for the AP release and the at least one terminal ID included in the terminal acceptance instruction which has arrived. At the time, in the case that the intrinsic ID is used as the SSID for the AP release, the following process is performed. For example, eachAP10 stores the intrinsic ID on the storage device beforehand, and uses, for the terminal acceptance process, the SSID for the AP release that coincides with the SSID for the AP release that is stored beforehand, among the plurality of SSIDs for the AP release included in the terminal acceptance instruction. The multicast is applied, for example, in the case that a suitable communication environment may be provided no matter which of the plurality ofAPs10 theterminal5 is connected to. In the case that the multicast is executed, the time before theterminal5 is connected to theAP10 may be shortened compared to the case that terminal acceptance is sequentially instructed by the unicast.
• Or, the plurality of intrinsic IDs and identification information (stored beforehand by the individual APs10) of theAPs10 corresponding to the individual intrinsic IDs are associated and included in the terminal acceptance instruction, and the intrinsic ID that the identification information coincides with is used for the terminal acceptance process. The identification information of theAP10 may be the one that may be distinguished among theAPs10. For example, for the identification information of theAP10, the address of theAP10 or the SSID used at normal time (other than the time of the AP release) may be applied.
• Also, in the case of not executing assignment of the plurality ofterminals5 to the plurality of APs10 (for example, in the case of focusing on force-out from the base station4), the terminal acceptance instruction including the common ID targeted at all theAPs10 and the terminals IDs of all theterminals5 that are switching targets may be multicasted or broadcasted.
• Also, transmission of the terminal acceptance instruction related to oneterminal5 to oneAP10 may be performed once or separately in a plurality of times. Also, the terminal acceptance for oneterminal5 may be instructed simultaneously to the plurality ofAPs10.
• The following description ofFIG. 5 illustrates an example that the release/restoration manager101 deduces thecorresponding AP10 by a terminal unit, and transmits the terminal acceptance instruction including one SSID for the AP release and one terminal ID that may be accepted to therelevant AP10 by the unicast. Of course, the transmission of the terminal acceptance instruction may be also executed by AP unit.
• In theAP10 which has received the terminal acceptance instruction, the release/restoration manager101 searches theterminal5 of an acceptance target using thewireless communication function103 based on the SSID for the AP release included in the terminal acceptance instruction (FIG.5<10>). The search may be performed depending on whether or not the SSID for the AP release identical to the SSID for the AP release included in the terminal acceptance instruction is included in signals (line establishment request) from a wireless LAN terminal received by thewireless communication function103. At the time, in the case that the signals including the SSID for the AP release are not received, that is, theterminal5 of the acceptance target is not found (the connection is impossible), the release/restoration manager101 sends a terminal confirmation impossibility notice to thecontroller73 of the disaster server7 (FIG.5<11>).
• In contrast, in the case that the line establishment request including the SSID for the AP release is detected by the search, theAP10 compares the terminal ID included in the detected line establishment request with the terminal ID included in the terminal acceptance instruction. In the case that the terminal IDs do not coincide in a result of comparison, theAP10 sends the terminal confirmation impossibility notice to the disaster server7 (FIG.5<11>). The terminal confirmation impossibility notice may include the SSID for the AP release and the terminal ID included in the terminal acceptance instruction.
• The processes <7> to <10> described above are executed in units of theterminal5 whose position information is registered in the positioninformation management DB721. In the example ofFIG. 5, when the terminal confirmation impossibility notice is received, thecontroller73 starts a process for instructing the acceptance to analternative AP10 for theterminal5 related to the terminal confirmation impossibility notice. At the time, thecontroller73 may specify theAP10 that has been incapable of accommodating thetarget terminal5 from a source address of the terminal confirmation impossibility notice (the address of the AP10), for example. Thecontroller73 which has received the terminal confirmation impossibility notice by the process <11> requests the AP position/terminal position information including the terminal ID in the terminal confirmation impossibility notice and the address of theAP10 to theposition information manager72 in order to search the alternative AP10 (FIG.5<12>), and obtains a response including the relevant AP position/terminal position information from the position information manager72 (FIG.5<13>). The response includes the address of thealternative AP10.
• Then, similarly to <9>, the terminal acceptance instruction is transmitted to the corresponding AP10 (alternative AP10) (FIG.5<14>), and theAP10 searches the terminal5 (FIG.5<15>). That is, theAP10 searches the line establishment request from theterminal5 including the SSID for the AP release identical to the SSID for the AP release included in the terminal acceptance instruction, and compares the terminal ID included in the line establishment request with the terminal ID included in the terminal acceptance instruction. In the case that the terminal IDs coincide in a result of comparison, theAP10 executes a line establishment procedure with the terminal (FIG.5<16>). When AP connection is completed, theterminal5 cancels the connection with thebase station4. Of course, cancellation of the connection with thebase station4 may be executed before the AP connection is completed.
• Also, in the procedure inFIG. 5, theAP10 may have a configuration that theAP10 forcibly shifts to a connectable state with a wireless LAN terminal with the reception of the AP release instruction by theAP10 as a trigger. For example, when thewireless module115 and theantenna114 in charge of thewireless communication function103 are in an operation stop state due to power supply stoppage or the like, in the case that theCPU111 receives the AP release instruction from the IP-IF controller104, theCPU111 starts power supply to thewireless module115 and theantenna114, and attains a state capable of the connection (line establishment) with theterminal5.
• Also, for example, in the case that the number of theterminals5 whose position information is registered in the positioninformation management DB721 is smaller than a predetermined threshold (there is a margin in the number of theterminals5 connected to the base station4), thecontroller73 may transmit an operation stop instruction to theAP10. TheCPU111 which has received the operation stop instruction stops the power supply to thewireless module115 and theantenna114 so that theterminal5 continues the connection with thebase station4.
• Also, in the case that the number of theterminals5 whose position information is registered in the positioninformation management DB721 is smaller than the predetermined threshold (there is a margin in the number of theterminals5 connected to the base station4), thecontroller73 may apply the configuration of not transmitting the AP release instruction including the terminal ID of aspecific terminal5 to theAP10. In this case, since theAP10 is not provided with the terminal ID, in the line establishment request from theterminal5, even when the SSID for the release coincides, the terminal ID does not coincide. As a result, theterminal5 maintains the connection state with thebase station4 without being able to be connected to theAP10.
• In the AP release sequence upon disaster occurrence described above, thebase station controller3 transmits the ETWS-Paging signals including the SSID for the AP release to thebase station4 with the reception of an emergency call as a trigger.
• In the case that the AP release is to be executed, the ETWS-WriteReplace signals including the SSID for the AP release and the ETWS information are transmitted to thebase station controller3, and the ETWS-Paging signals including the SSID for the AP release are transmitted to all theterminals5 connected to thebase station4. Thus, theindividual terminals5 may acquire the SSID for the AP release. Also, theindividual terminals5 may acquire the ETWS information from the reporting information or the ETWS-Paging signals.
• Also, thecontroller73 of thedisaster server7 transmits a release instruction to theAP10. TheAP10 which has received the release instruction searches the peripheralaccommodatable terminal5 and tries to establish a line. By the search, theAP10 may receive the signals (line establishment request) from theterminal5 requesting the line connection using the SSID for the AP release. In the case that the received signals from theterminal5 include the terminal ID included in the terminal acceptance instruction, theAP10 performs the line establishment procedure with theterminal5 and secures a communication band.
• When theterminal5 instructed by the terminal acceptance instruction is not found, accommodation of theterminal5 may be instructed to the alternative AP10 (adjacent different AP10). In the case that the line with theterminal5 is disconnected due to movement of theterminal5 or the like, a terminal disconnection notice (including the SSID for the AP release and the terminal ID) is transmitted from theAP10 to thedisaster server7. In this case, thedisaster server7 performs a process similar to the one when the terminal confirmation impossibility notice is received, and may transmit the terminal acceptance instruction to the alternative AP10 (for example, the adjacent different AP10).
• <<(3) Position Registration Sequence (Access Point)>>
• FIG. 6 illustrates one example of the position registration sequence of theterminal5 using theAP10. InFIG. 6, theterminal5 transmits the position information to theAP10 at least once (for example, in the line establishment procedure) (FIG.6<1>). The position information may include the terminal ID, the address of theterminal5, the position information (x/y coordinates) of theterminal5, and the identification information of theAP10.
• When the position information is received, theAP10 generates a packet including the position information, and transmits the packet (position information data) through theIP network8 to the disaster server7 (FIG.6<2>). In thedisaster server7, the position information data is stored in the positioninformation management DB721 by theposition information manager72. Also, thedisaster server7 may receive a source address of the packet including the position information as specific information of theAP10 to which theterminal5 is connected. In this way, for eachAP10 registered in theAP information DB722, the information of theterminals5 connected with theindividual APs10 by the AP release is managed. Also, the position registration of theterminal5 using theAP10 may be executed at an appropriate timing as needed.
• Also, the first position information data is handled as a notice indicating a success of the line establishment procedure in thedisaster server7. That is, thedisaster server7 may recognize the connection (line establishment) of theterminal5 and theAP10 by receiving the position information data. Of course, prior to the position registration, after the procedure of FIG.5<16> for example, the notice indicating the line establishment success may be transmitted to thedisaster server7.
• <<(4) Sequence Upon Aftershock>>
• FIG. 7 illustrates an example of the sequence upon an aftershock (the sequence of transmitting the ETWS information (emergency information) through the AP). An emergency call (including the ETWS information) is sent from thePSAP1 every time an earthquake occurs. Therefore, after the occurrence of an earthquake, every time an aftershock of the earthquake occurs, an emergency call (including the ETWS information) is sent from thePSAP1. The emergency call is received by the core network apparatus21 (FIG.7<1A>). The emergency call is also received by the disaster server7 (FIG.7<1B>).
• In thedisaster server7 which has received the emergency call (ETWS information), thecontroller73 inquires of theposition information manager72 the information of theterminal5 to transmit the ETWS information (FIG.7<2>: terminal information acquisition request). Theposition information manager72 refers to the positioninformation management DB721, reads the information of theterminal5 whose position is registered, and returns it to the controller73 (FIG.7<3>: terminal information acquisition response).
• Thecontroller73 generates the packet including the ETWS information, sets the address of theterminal5 included in the information of theterminal5 obtained from theposition information manager72 to the packet, and sends it out to the IP network8 (FIG.7<4>: via-AP ETWS information transmission instruction).
• In theAP10 which has received the packet (via-AP ETWS information transmission instruction), the ETWSinformation transmission process102 is executed, and the baseband signals including the ETWS information are given to the wireless communication function103 (wireless module115) (FIG.7<5>: ETWS transmission instruction). The wireless communication function103 (wireless module115) generates RF signals including the ETWS information and transmits them from the antenna114 (FIG.7<6>: ETWS transmission).
• By the sequence illustrated inFIG. 7, theterminal5 may receive the ETWS information which is receivable when thebase station4 is connected via theAP10 even after switching to theAP10. That is, while the line with theAP10 is maintained, the ETWS information to be notified when an aftershock occurs or the like is notified from theAP10 to theterminal5 through thedisaster server7.
• <<(5) Safety Confirmation Sequence Upon Disaster Occurrence>>
• Theterminal5 connected to theAP10 may utilize the information exchange service like the bulletin board system and Twitter® using the data for the UI display prepared in thedisaster server7, by utilizing theWeb function71 of thedisaster server7. A user of theterminal5 may utilize the information exchange service for safety confirmation.
• FIG. 8 illustrates one example of the safety confirmation sequence (information exchange service utilization sequence) upon disaster occurrence. For example, theposition information manager72 of thedisaster server7 gives a URL provision request for theterminal5 to theWeb function71 with the position registration of theterminal5 to the positioninformation management DB721 as a trigger (FIG.8<1>).
• TheWeb function71 generates the packet including an address (URL (Uniform Resource Locator)) of an information exchange service site such as the bulletin board system or Twitter® supported by theWeb function71, and sends the packet through theIP network8 to theAP10 accommodating the terminal5 (FIG.8<2>).
• In theAP10 which has received the packet, for example, the release/restoration manager101 uses thewireless communication function103, and sends signals including the URL in the packet to the terminal5 (FIG.8<3>, <4>). Also, the release/restoration manager101 stores the URL in a predetermined storage device (for example, a nonvolatile memory (the flash ROM734)).
• A processor (for example, a CPU) provided in the terminal performs the following process by executing a program (an application to be used upon a disaster by the terminal5 (an application for the time of a disaster, for example. It does not have to be a specialized application as long as equivalent operations are possible)) stored in a storage device provided in theterminal5. That is, when the URL is received, the processor of theterminal5 registers the URL to the application for the time of a disaster. Thereafter, when an access operation to the registered URL is performed by a user, user data is transmitted to the AP10 (FIG.8<5>).
• The user data includes the URL of an access destination, and in theAP10, the release/restoration manager101 checks the URL. In the case that the URL is not the same as the URL (specific URL) for the information exchange service site registered in theflash ROM734, the user data is not transferred to theIP network8. Thus, in theterminal5, timeout of Web access occurs, resulting in an error.
• In this way, in the case that the URL of a Web site that theterminal5 tries to access is not the specific URL, the access to the Web site is interrupted by theAP10. In contrast, in the case that the URL included in the user data is the same as the specific URL, the packet including the user data is generated and transmitted through theIP network8 to the disaster server7 (FIG.8<6A>).
• In thedisaster server7, the user data is received by theWeb function71. TheWeb function71 sends a position information request, and inquires of theposition information manager72 the information of theterminal5 which has transmitted the user data (FIG.8<7>).
• Theposition information manager72 reads the information of theterminal5 according to the position information request from the positioninformation management DB721, and returns a position information response including the read information to the Web function71 (FIG.8<8>).
• When the user data is an access request to the information exchange service site, theWeb function71 reads the data for the UI display (display data) of the information exchange service site according to the access request from theWeb DB711, and generates and transmits a packet for theterminal5 including the display data (FIG.8<9>). The packet is received by theAP10, and theAP10 transmits the display data to theterminal5.
• In theterminal5, A web browser executed by the CPU displays a Web page of the information exchange service site using the display data on a display not illustrated in the figure. A user of theterminal5 may exchange information including the safety confirmation with persons concerned using the information exchange service site, by inputting information using the web page.
• The display data is created on the text basis for example, and an amount of data is suppressed compared to a general Web site using images and moving images. Therefore, since an amount of communication data related to theAP10 is reduced, overloading theAP10 by utilization of the information exchange service site may be avoided, and influence on the communication between theAP10 and the other terminals may be avoided.
• Also, by URL check in theAP10, theterminal5 is turned to a state that an accessible Web site is limited to the information exchange service site. By such limitation, influence on the communication of theother terminals5 by transmission and reception of a large amount of data through free Web access of theterminal5 may be avoided. A process related to Web access limitation (access denial except for a specific site) may be executed in theterminal5 by setting of the Web browser in theterminal5 for example.
• However, a configuration related to the Web access limitation described above may be omitted. In the case that the configuration related to the Web access limitation is omitted, for example, the URL of the information exchange service site is registered (bookmarked) beforehand in the Web browser of theterminal5 or the application for the information exchange service site. In this case, a user of theterminal5 connected to theAP10 may access the information exchange service site using a bookmark.
• <<(6) Access Point Restoration Sequence after Disaster Occurrence>>
• FIG. 9 illustrates one example of the AP restoration sequence after disaster occurrence. InFIG. 9, when a state that a predetermined restoration condition in thebase station4 is satisfied is attained, state information indicating a restoration state is transmitted from thebase station4. The state information reaches thecarrier management apparatus6 through thebase station controller3 and the core network2 (FIG.9<1>). Thecarrier management apparatus6 sends the state information through theIP network8 to the disaster server (FIG.9<2>). Examples of the restoration condition are the restoration from a failure state of thebase station4, the restoration from a congestion state of the base station4 (congestion state cancellation), the number of theterminals5 connected to thebase station4 being smaller than the predetermined threshold, or the like.
• In thedisaster server7 which has received the state information, theposition information manager72 reads the information related to one terminal5 (information of theterminal5 and the AP10) from the positioninformation management DB721, and sends a BTS restoration notice including the information of theterminal5 and theAP10 to the controller73 (FIG.9<3>). When the BTS restoration notice is received, thecontroller73 generates a packet for theAP10 including the AP restoration instruction and the AP release SSID invalidation notice related to theterminal5, and transmits it to theAP10 using the information of the AP10 (FIG.9<4>). The AP restoration instruction and the AP release SSID invalidation notice include at least the SSID for the AP release to be invalidated, and the terminal ID of theterminal5 which is a force-out target. The AP restoration instruction and the AP release SSID invalidation notice are examples of a force-out instruction including an invalidation notice of the first information.
• In theAP10 which has received the packet, the release/restoration manager101 uses thewireless communication function103 to perform the force-out process to theterminal5 connected to theAP10 using the SSID for the AP release included in the AP release SSID invalidation notice (FIG.9<5>). That is, the release/restoration manager101 invalidates the SSID for the AP release related to theterminal5 as the force-out process. Thus, thewireless communication function103 disconnects the line with the terminal5 (FIG.9<6>).
• The AP restoration instruction and the AP release SSID invalidation notice are also transmitted from thedisaster server7 to the provider9 (charging server). The provider9 (charging server) which has received the AP restoration instruction and the AP release SSID invalidation notice cancels a temporary charging process stop state for theterminal5 specified by the SSID for the AP release and the terminal ID, and restarts the charging process to theterminal5.
• When disconnected from theAP10, theterminal5 receives reporting signals from thebase station4, and starts a connection procedure (line connection process) to the base station4 (cellular network) (FIG.9<7>). When the line connection process of theterminal5 and thebase station4 is completed, a line connection completion notice is transmitted from thebase station4 to the terminal5 (FIG.9<8>). Theterminal5 transmits the position information of itself to thebase station4 by a Measurement message (FIG.9<9>).
• The following operations are the same as the ones before disaster occurrence. That is, the position information is transmitted from thebase station4 to thebase station controller3, and transmitted through thecore network2 to the carrier management apparatus6 (FIG.9<10>, <11>, <12>). Thecarrier management apparatus6 generates the position information data and sends it to the disaster server7 (FIG.9<13>), and in thedisaster server7, theposition information manager72 registers the position information data to the positioninformation management DB721.
• The above-described restoration sequence may be executed under the following situation. That is, it is executed at a timing of using the information indicating the restoration situation of thebase station4. Whether or not thebase station4 has restored is determined depending on whether or not thebase station4 has returned to a normal process. That is, in the case that thebase station4 falls into the failure state or the congestion state due to disaster occurrence, a state of being incapable of registering the position information to the carrier management apparatus6 (non-registerable state) or a state of needing time for registration (delay state) starts. Update of the positioninformation management DB721 of thedisaster server7 is executed with update of the positioninformation management DB63 of thecarrier management apparatus6 as a trigger. Therefore, when thecarrier management apparatus6 is turned to the position information non-registerable state or the delay state, thedisaster server7 is similarly turned to the non-registerable state or the delay state. For example, in the case that a difference between the time of a time stamp to the position information and the current time exceeds a threshold (time) to be considered as being normal (not delayed), the delay state is determined.
• When thebase station4 is turned to a state of performing the normal process, the non-registerable state and the delay state in thecarrier management apparatus6 are cancelled. Theposition information manager72 of thedisaster server7 monitors an updating situation of the positioninformation management DB721. Then, in the case that the situation of the non-registerable state or the delay state for the position information of the terminal5 from acertain base station4 is shifted to the situation that the position information is normally updated in a range without a delay, theposition information manager72 may determine that thebase station4 has restored. In the case that such a determination is made, the operations of <3> and thereafter illustrated inFIG. 9 are performed.
• The force-out process of the terminal5 from theAP10 is executed in units of the AP. Of course, it may be executed for each terminal5 in units of the AP. By execution in units of the AP, compared to the case of returning theterminals5 of the plurality of APs to the connection state to thebase station4, the concentration of the line connection requests from theterminals5 to thebase station4 is avoided. Thus, sudden load application to thebase station4 may be avoided. However, the process of returning theterminals5 connected to the plurality ofAPs10 to the connection state to thebase station4 may be executed temporarily.
Second Embodiment
• Next, the wireless communication system according to the second embodiment will be described. Since the second embodiment has features that are in common with the first embodiment, the same signs are attached and descriptions of the common features are omitted.FIG. 10 illustrates a configuration example of the wireless communication system in the second embodiment. The configuration of the wireless communication system illustrated inFIG. 10 is similar to the configuration of the wireless communication system in the first embodiment illustrated inFIG. 1. However, inFIG. 10, the plurality (three, inFIG. 10) of the base stations4 (BTSes) are illustrated for the base station controller3 (RNC), and the plurality (six, inFIG. 10) ofAPs10 connected to theIP network8 are illustrated.
• <Configuration>
• FIG. 11 is a diagram schematically illustrating thedisaster server7, theAP10 and theterminal5. InFIG. 11, thedisaster server7 includes theWeb function71, theposition information manager72, thecontroller73 that performs the ETWS process (release, restoration control) and the AP assignment control, and the IP-IF controller74.
• TheWeb function71 has a text-basis GUI andCUI engine71A, and supports a bulletinboard system function71B and a Twitter function (tweet function)71C. TheAP10 performs the process for limiting the Web access of theterminal5 to the information exchange service site provided in thedisaster server7, as described usingFIG. 8, as adata communication process10A. Theterminal5 has anapplication5A to be used in the case of being connected to theAP10 by the switching process as the application for the time of a disaster. Theapplication5A may be a general-purpose application (a Web browser, for example), or may be an exclusive application. Theapplication5A is a function achieved by the execution of the program by the processor (CPU) provided in theterminal5. By Web access limitation, a communication amount of theAP10 may be suppressed.
• For example, data of the bulletin board system or Twitter® generated using theapplication5A is sent as the user data to thedisaster server7 by thedata communication process10A of theAP10. In thedisaster server7, the user data is received by theWeb function71. TheWeb function71 controls the bulletinboard system function71B and the Twitter function71C according to contents of the user data. TheWeb function71 transmits a processing result of the bulletinboard system function71B or the Twitter function71C to the terminal.
• Also, theterminal5 has a positioninformation transmission function5B, and theAP10 has a terminal information transmission function andterminal authentication function10B. TheAP10 checks the SSID obtained from theterminal5 using the terminal authentication function, and does not perform the line establishment procedure of theterminal5 when the SSID is not the SSID for the release. Also, the position information transmitted by the terminal using the positioninformation transmission function5B is transmitted to thedisaster server7 using the terminal information transmission function in theAP10. At the time, to terminal information, the AP information (the information of theAP10 to which theterminal5 is connected) is set. The terminal information and the AP information are stored in the positioninformation management DB721 by theposition information manager72.
• Also, theterminal5 has anapplication5C for the connection process to the AP of the wireless LAN. Theapplication5C performs the connection process (line establishment process) with theAP10 using the SSID for the release, and a line disconnection process accompanying the invalidation of the SSID for the release. Also, by theapplication5C, the ETWS signals are received from theAP10.
• Also, the functions of thedisaster server7 and theAP10 illustrated inFIG. 11 may be achieved by the hardware configuration illustrated inFIG. 2 andFIG. 3. Theterminal5 may have the hardware configuration similar to the AP10 (seeFIG. 3), for example. By the execution of the program stored in the auxiliary storage device by the CPU, the function of theapplication5A (a browsing function of the bulletin board system and Twitter, an information input and sending function to the bulletin board system and Twitter), the positioninformation transmission function5B, and the connection process based on theapplication5C may be achieved.
• <<Assignment Algorithm of AP>>
• Next, assignment algorithm of the AP will be described. A process of assigning the plurality ofterminals5 to the plurality ofAPs10 is performed as follows.
• (1) Based on the position information of theterminal5 and field intensity, theAP10 from which theterminal5 may receive radio waves is mapped by thecontroller73 of thedisaster server7.
• (2) There is a possibility that the connection of theterminals5 is concentrated at theAP10 havingmany terminals5 that may receive the radio waves. Therefore, thecontroller73 selects and averages theterminals5 receiving the radio waves from the plurality ofAPs10.
• (3) Averaging is performed by notifying, from thedisaster server7, the terminal IDs of theterminals5 to be accommodated in theindividual APs10.
• (4) In the case of receiving the connection request from theterminal5 having the notified terminal ID, theAP10 performs the connection process on condition that the SSID for the release coincides.
• (5) In the case that theAP10 is incapable of receiving the connection request from theterminal5 whose terminal ID is notified, there is a possibility that thetarget terminal5 has moved or the radio waves from theterminal5 are not suitably received due to an obstacle or the like. In this case, theAP10 transmits a connection instruction to anadjacent AP10 which is a different candidate.
• (6) The restoration is executed in units of theAP10, and sudden overloading of thebase station4 is avoided.
• FIG. 12 illustrates an example of a distribution of theterminals5 and access candidate routes. In the example illustrated inFIG. 12, to thebase station controller3, a base station A and a base station B are connected as the twobase stations4. Also, as the plurality ofAPs10, four AP#1-AP#4 are illustrated. Further, as the plurality ofterminals5, 12 pieces of the terminals5 (terminals ID“1”-ID“12”: described as “terminals ID1-ID12” hereinafter) are illustrated.
• InFIG. 12, the individual terminals ID1-ID12 may be connected to thebase station4 and theAP10 from the respective positions as follows. Specifically, the terminals101-107, the terminal ID10 and the terminal ID11 may be connected to the base station A based on the respective positions. The terminal ID9 and theterminal ID12 may be connected to the base station B based on the respective positions. The terminal ID8 may be connected to one of the base station A and the base station B based on the position.
• On the other hand, the terminal ID1 may be connected (access) to theAP#1, theAP#2, or theAP#3. A route indicating the AP (connection candidate) that the terminal ID1 may be connected like this becomes the access candidate route to the AP. On the contrary, a switching route from one of the AP#1-AP#3 to the base station A becomes the access candidate route to thebase station4. Similarly to the terminal ID1, the terminal102 may be also connected to one of the AP#1-AP#3, and these APs become connection candidates. Each of the terminal ID3 and the terminal104 may be connected to theAP#1 or theAP#2, and these APs become the connection candidates. Each of the terminal ID5 and the terminal ID6 may be connected to theAP#2 or theAP#3, and these APs become the connection candidates.
• Also, each of the terminal ID7, the terminal ID10 and the terminal ID11 may be connected to theAP#2, theAP#3 or theAP#4, and these APs become the connection candidates. Each of the terminal ID8 and the terminal109 may be connected to theAP#3 or theAP#4, and these APs become the connection candidates. Then, the terminal ID12 may be connected to theAP#4 alone, and theAP#4 becomes the connection candidate.
• FIG. 13A illustrates a stored content example of the positioninformation management DB721 at normal time,FIG. 13B illustrates a stored content example of the positioninformation management DB721 when a disaster occurs (or during a failure), andFIG. 13C illustrates a stored content example of the positioninformation management DB721 at the time of the restoration.
• In the examples illustrated inFIG. 13A,FIG. 13B andFIG. 13C, in the positioninformation management DB721, a table indicating propriety of the connection to one ormore APs10 corresponding to thebase station4, corresponding to the terminal ID and terminal position (x/y coordinates) of theterminal5, is stored. Also, in the table, identifiers (base station ID, AP-ID) of the base station (BTS)4 and theAP10 are stored. As one AP-ID, the address of theAP10 is included.
• As illustrated inFIG. 13A,FIG. 13B andFIG. 13C, based on a positional relation illustrated inFIG. 12, the base station A (BTS-A) corresponds to the AP#1 (AP1), the AP#2(AP2) and the AP#3(AP3). Also, the base station B (BTS-B) corresponds to the AP#4 (AP4). Also, in the example inFIG. 13A, in the table, “OK”, “NG”, “B connection”, and “A connection” are registered as statuses (states) indicating the correspondence relation between the terminal5 and theAP10.
• Here, the state “OK” indicates that theAP10 or thebase station4 becomes the connection candidate when the AP is released regarding theterminal5. On the contrary, the state “NG” indicates that theAP10 or thebase station4 does not become the connection candidate (unconnectable) when the AP is released regarding theterminal5. Also, the state “B connection” indicates thebase station4 to which theterminal5 is connected, and is registered for the AP nearest to thebase station4 among one ormore APs10 corresponding to the base station4 (for which a communication range with theterminal5 overlaps or coincides with the cell of the base station4).
• For example, in contents illustrated inFIG. 13A, the terminal ID1-the terminal ID6 are connected to the base station A, and the state “B connection” indicating the connection with the base station A is registered for theAP#2 which is theAP10 nearest to the base station A. TheAP10 for which the state “B connection” is registered naturally becomes the connection candidate regarding thecorresponding terminal5. In other words, the state “B connection” indicates that the connection is “OK” for thecorresponding terminal5, and indicates that the AP release instruction is to be transmitted preferentially to theAP10. That is, for the terminal ID1-the terminal ID6, it is indicated that the AP release instruction for accepting the terminal ID1-the terminal ID6 is to be transmitted to theAP#2. Also, the state “A connection” (seeFIG. 13B,FIG. 13C) indicates theAP10 to which theterminal5 is connected, and indicates that the connection is OK (it is the connection candidate) for thebase station4 corresponding to theAP10. In this way, for theindividual terminals5 connected to theindividual base stations4, mapping to theindividual APs10 is executed.
• FIG. 14 is a flowchart illustrating detail of the AP assignment process. Also,FIG. 15A toFIG. 15D are explanatory drawings of the AP assignment process. The AP assignment process illustrated inFIG. 14 is executed by the controller73 (CPU731). The AP assignment process is started in the case that thedisaster server7 receives an emergency call, for example. InFIG. 14, first, thecontroller73 reads (loads) a coordinate table (ID“1”: (xxx1,yyy1)-ID“12”: (xxx12,yyy12)) of theterminals5 stored in the positioninformation management DB721 to a work area (for example, the SDRAM732) (01).
• Next, thecontroller73 reads (loads) the position information (coordinates) of theindividual APs10 from theAP information DB722 to the work area, and calculates distances between the individual terminals5 (ID“1”-ID“12) and the individual APs10 (AP#1-AP#4) using the coordinates of theindividual terminals5 and the coordinates of the individual APs10 (02).
• Next, thecontroller73 determines theAP10 connectable to theindividual terminals5 from calculation results in02 (03). For example, by prior radio wave measurement (experiment), a distance at which theterminal5 may receive the radio waves from the individual APs10 (AP#1-AP#4) is obtained as a threshold. The threshold is stored beforehand in theflash ROM734, for example. As a result, as illustrated inFIG. 12, the correspondence relation (the connection candidate route when the AP is released) based on the positions of the base stations A and B, the APs #1-#10, and the terminal ID1-the terminal ID12 is determined. Further, a table having the contents illustrated inFIG. 13A is created.
• Next, thecontroller73 lists up the APs to be the connection candidates of theindividual terminals5 based on a determination result of03 (04). Then, thecontroller73 calculates theAP10 which is turned to the connection candidate regarding the plurality of terminals5 (05). Thus, theAP10 at which theterminals5 are to be concentrated is predicted.
• FIG. 15A illustrates the processes of04 and05. In the case that the relation of the connection candidates between the individual terminals ID1-ID12 and the individual APs #1-#4 is the contents illustrated inFIG. 13A, the relation may be schematically illustrated as illustrated inFIG. 15A. As illustrated inFIG. 15A, the connection candidates of the terminal ID1-the terminal ID12 include theAP#2 or theAP#3 except for the terminal ID12, and the terminal ID1-the terminal ID11 are concentrated at theAP#2 and theAP#3. Therefore, by the processes after06, the connection candidates are averaged.
• Next, thecontroller73 determines an assigning direction of the terminals based on the AP position information (the coordinates of the individual APs) and the information of the AP redundantly selected as the connection candidate from the plurality of terminals (06). The assigning direction indicates whether to assign the individual terminals in a direction of theAP#1→theAP#4 or in a direction of theAP#4→theAP#1.
• Next, thecontroller73 performs assignment from theAP10 selected as the connection destination candidate of theterminal5 most often to the AP selected least often (07). Then, thecontroller73 assigns theterminals5 so as to equalize the connection (scheduled) numbers of theterminals5 to theindividual APs10, that is, to be close to “the number of theterminals5 connected to oneAP10=the total number of the terminals/the number of the APs” (08).
• The processes of06-08 will be described usingFIG. 15B,FIG. 15C, andFIG. 15D. In the state ofFIG. 15A, thecontroller73 determines the assigning direction to be theAP#1→theAP#4, for example. Then, the APs to be the connection destinations of the individual terminals ID1-ID12 are determined in the order of theAP#1→theAP#2→theAP#3→theAP#4. At the time, the total number “12” of theterminals5 is taken into consideration, and the connection destinations for the individual terminals ID1-ID12 are determined so that threeterminals5 each are assigned to the individual AP#1-AP#4.
• As illustrated inFIG. 15B, for the terminals ID1-ID3, the connection to theAP#1 overlapping with theAP#2 is determined. Next, as illustrated inFIG. 15C, for the terminal ID4, based on an average value “3” of the number of the terminals per AP, theAP#2 is determined as the connection destination. Also, as the remaining terminals to be connected to theAP#2, the terminals ID5 and ID6 are determined. Then, the terminals of the connection destinations are determined so that the remaining terminals ID7-ID12 are equally assigned to the remainingAP#3 andAP#4. As a result, as illustrated inFIG. 15D, theAP#3 is determined as the connection destination of the terminal ID7, the terminal ID9, and theterminal ID11, and theAP#4 is determined as the connection destination of the terminal ID8, the terminal ID10, and the terminal ID12.
• The above-described processes of01-08 correspond to a mapping process before disaster occurrence in the first embodiment. An assignment result prepared in the processes of01-08 becomes the contents illustrated inFIG. 15C. By using such an assignment result (assignment prediction), the AP release instruction for the connection of the individual terminals ID1-ID12 is transmitted to the individual AP#1-AP#4. The following09 and thereafter are the processes in theAP10 or theterminal5 after the AP release instruction is transmitted to the individual AP#1-AP#4 according to the assignment prediction.
• In09 inFIG. 14, theAP10 executes the connection process of theterminal5 in the case of receiving the connection request (line establishment request) from theterminal5 including the SSID for the AP release and the terminal ID notified from thedisaster server7, and rejects the connection request from theterminal5 having the terminal ID other than the notified terminal ID. Theterminal5 rejected in09 tries the connection to another AP10 (10). For example, the terminal ID1 is in an environment of being capable of receiving the radio waves of theAP#1 and theAP#2. In the case that the terminal ID1 transmits the line connection request to theAP#2, theAP#2 rejects the line connection request since the terminal ID of the terminal ID1 has not been received. Therefore, the terminal ID1 transmits the line connection request to theAP#1 which is anotherAP10.
• In11 inFIG. 14, theAP10 activates a predetermined timer with the reception of the AP release instruction as a trigger. In the case that the line establishment request from theterminal5 specified by the AP release instruction is received before the timer expires, the line with theterminal5 is established. In contrast, in the case that the timer expires, theAP10 sends the terminal confirmation impossibility notice to thedisaster server7. In thedisaster server7, the terminal confirmation impossibility notice is received, the table (FIG. 13A) is referred to, and the AP release instruction specifying another connection candidate (AP10) related to theterminal5 is transmitted to anotherAP10 corresponding to the next connection destination. AnotherAP10 performs the above-described process of09, and establishes the line with theterminal5 with the line establishment request of theterminal5 as a trigger. Also, the processes of08-11 are looped until the line between the terminal5 and theAP10 is established or there is nomore AP10 of the connection destination.
• Regarding the process of11, instead of the above-described configuration, the following configuration (modification) may be also applied. That is, thecontroller73 of thedisaster server7 activates the predetermined timer with notification of the terminal ID to theAP10 as a trigger for example. In the case that the position information data of thecorresponding terminal5 is registered from theAP10 to the positioninformation management DB721 for example before the timer expires, it is determined that theterminal5 is normally connected to theAP10 of the connection candidate. In contrast, in the case that the timer expires without the position information being registered, thecontroller73 assigns theterminal5 to anotherAP10. Then, the AP release instruction including the terminal ID of theterminal5 is notified to anotherAP10. In the modification, thedisaster server7 determines a result of the line establishment related to the AP release instruction using the timer. Therefore, the transmission of the terminal confirmation impossibility notice may be omitted.
• As above, in the case that all theterminals5 scheduled to be switched are connected with the correspondingAPs10, the processes inFIG. 14 are ended.FIG. 13B illustrates a mapping result of theindividual terminals5 to theAPs10 in a disaster. That is,FIG. 13B illustrates table contents after performing the assignment process inFIG. 14 using the assignment result illustrated inFIG. 15D.
• InFIG. 13B, the terminals ID1-ID7 and the terminal ID11 are connected to the correspondingAPs10 according to the determination result of the connection destinations illustrated inFIG. 15D. In contrast, the terminal ID9 is connected to theAP#4 which is anotherAP10 as a result of being incapable of being connected to theAP#3 that is a scheduled connection destination. Also, the terminal ID10 is connected to theAP#3 which is anotherAP10 as a result of being incapable of being connected to theAP#4 that is the scheduled connection destination.
• FIG. 13C illustrates the connection state at the time of the restoration from a failure of the base station B (BTS-B) (when terminal accommodation by the base station B is restarted). By thedisaster server7 sending the AP restoration instruction and the release SSID invalidation notice to theAP#4, theAP#4 disconnects the connection (line) with the terminal ID8, the terminal ID9 and the terminal ID12 that are subordinate. Thus, the terminal ID8, the terminal ID9 and the terminal ID12 are respectively connected to the base station B. Thus, inFIG. 13C, as the correspondence relation of each of the terminal ID8, the terminal ID9 and the terminal ID12 to theAP#4, the state “B connection” is stored. Also, when the base station A (BTS-A) is restored, the remainingterminals5 may be also returned to the connection of the base station A or the base station B, and returned to the state at normal time.
• FIG. 16 illustrates another example of the assignment state to the AP#1-AP#4 of the individual terminals5 (ID“1”-“12”) stored in the positioninformation management DB721 during a fault (failure) of the base stations A and B, andFIG. 17 illustrates the state when the base station A is restored from the state illustrated inFIG. 16. In the examples inFIG. 16 andFIG. 17, an example that the terminal ID7, the terminal ID8 and the terminal ID9 connected to theAP#3 during the failure are returned to the original state of being connected to the base station A is illustrated.
Effects of Embodiments
• The wireless communication system described in the first and second embodiments includes thedisaster server7 capable of recognizing the distribution of theAPs10 and theterminals5 beforehand from the position information of thebase station4 and assigning theterminals5 to thepredetermined APs10. Thedisaster server7 is one example of a server. In the embodiment, the SSID for the AP release is supplied to theterminal5 connected to thebase station4 with the generation of an emergency call as a trigger. On the other hand, thedisaster server7 gives the SSID for the AP release and the terminal ID of theterminal5 to theAP10 which is the connection destination candidate of theterminal5. Thus, theAP10 establishes the line with theterminal5 with the reception of the line connection request including the SSID for the AP release and the terminal ID of theterminal5 itself transmitted from theterminal5 as a trigger. Thus, the connection destination of theterminal5 is switched from thebase station4 to theAP10 which is present near (whose communication area overlaps with) thebase station4.
• Therefore, under the situation that a failure or congestion may occur in thebase station4 due to a disaster or an accident or the like, alternative communication means may be provided without making users be conscious. Also, by reducing the number of the terminals connected to thebase station4, the congestion of thebase station4 may be avoided. Also, thedisaster server7 assigns the plurality ofterminals5 to the plurality ofAPs10 so as not to generate a deviation among the APs regarding the plurality ofterminals5 to be separated from thebase station4. Thus, theindividual terminals5 may secure predetermined communication quality at theAP10 of the connection destination, and the occurrence of the congestion in theAPs10 may be avoided.
• Also, in the embodiment, a connection change from thebase station4 to theAP10 of theterminal5 and a connection change from theAP10 to thebase station4 are controlled through the AP release instruction, the AP restoration instruction and the release SSID invalidation notice by thedisaster server7. Through the AP release and restoration instructions, temporary stoppage of the charging process related to the wireless LAN utilization of the terminal using the SSID for the AP release and the cancellation of the temporary stoppage in the provider9 (charging server) may be automatically executed. In other words, regarding the utilization of the released AP10 (wireless LAN), conduct of a special operation for stopping charging by a user may be avoided. Also, by cancelling the temporary stoppage of the charging process using the AP restoration instruction, a period during which the utilization of theAP10 is released for free may be shortened (the charging process may be restarted at the point of time when there is no more need for free release).
• Further, in the embodiment, thedisaster server7 includes theWeb function71 for operating its own Web site that may be operated with a small amount of data, and theAP10 is controlled such that the access to the Web site alone is made possible in a disaster. Thedisaster server7 may suppress an amount of data communication by permitting the Web access to its own Web site (information exchange service site) alone.
• Thus, while the line connection state may be provided for more users, the users of theterminals5 may execute information exchange for the safety confirmation or the like using the information exchange service site. Also, by providing such an information exchange service site, safety confirmation means suitable for communication resources secured in a disaster may be provided.
• In other words, conventionally, when a disaster occurs, there is no guarantee that a line is established even when the user (terminal5) disconnected from thebase station4 tries the connection to the wireless LAN, and there is no guarantee that communication for excellent safety confirmation may be executed even when the line is established. In contrast, according to the present embodiment, since theAP10 enables the utilization of its own information exchange service site alone, theterminal5 may secure a communication band at a high probability, and execute the information exchange (information transmission, information acquisition) for the safety confirmation or the like under a proper environment regarding transmission and reception of information through the information exchange service site.
• Also, in the embodiment, the user (terminal5) is managed in units of the access point apparatus. Therefore, a community in a specific area is easily constructed, and means for broadcasting needed information in units of the access point apparatus may be provided.
• All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.

Claims (11)

What is claimed is:

1. A wireless communication system, comprising:

a base station to which a terminal is connected;

an access point of a wireless LAN connected with the terminal instead of the base station when an emergency call is sent; and

a server,

the base station supplying first information to be used for acceptance by the access point to a terminal connected to the base station according to the sending of the emergency call,

the server including:

a storage device configured to store a correspondence relation between a terminal connected to the base station and the access point; and

a controller configured to execute a process of transmitting to the access point an acceptance instruction of a terminal based on the correspondence relation according to the sending of the emergency call, the acceptance instruction including the first information, and

the access point performing a connection process with a terminal transmitting the first information, as one of conditions that the first information included in the acceptance instruction is coincident with the first information received from the terminal.

2. The wireless communication system according toclaim 1, wherein the controller of the server is configured to generate the correspondence relation by performing an assignment process using information of a plurality of terminals connected to one or more base stations and information of a plurality of access points that substitute the one or more base stations to assign each terminal to each access point.

3. The wireless communication system according toclaim 2, wherein the controller is configured to perform the assignment process so as to equalize the numbers of terminals assigned to each access point.

4. The wireless communication system according toclaim 1, wherein the storage device of the server is configured to store display data of an information exchange service site being a Web site created so that an amount of data communicated between the access point and the terminal is settled within a given range upon utilization,

wherein the access point or the terminal becomes a state of rejecting access to Web sites other than the information exchange service site, and

wherein the controller of the server is configured to perform a process of providing the terminal with an information exchange service by the information exchange service site, the information exchange service including a process of transmitting the display data to the terminal, according to access to the information exchange service site from the terminal connected to the access point.

5. The wireless communication system according toclaim 1, wherein the base station supplies second information included in the emergency call to a terminal connected to the station, and

wherein the controller of the server is configured to perform a process of transmitting the second information included in the emergency call to the terminal through the access point when the emergency call is received in the server.

6. The wireless communication system according toclaim 1, wherein the controller of the server is configured to perform a force-out process for the terminal of transmitting a force-out instruction to the access point, the force-out instruction including an invalidation notice of the first information, when a condition for reconnecting the terminal connected to the access point to the base station is satisfied.

7. The wireless communication system according toclaim 6, wherein the controller of the server is configured to execute the force-out process for the terminal for every access point in a case where there are a plurality of access points to which the plurality of terminals are connected.

8. The wireless communication system according toclaim 6, wherein the storage device of the server is configured to store position information of the terminal connected to the base station,

wherein the position information of the terminal is updated according to a position registration process to the base station of the terminal, and

wherein the condition is that an updating situation of the position information of the base station to the storage device becomes normal under a situation that the terminal is connected to the access point.

9. A server, comprising:

a storage device is configured to store a correspondence relation between a terminal connected to a base station and an access point connectable with the terminal instead of the base station; and

a controller configured to execute a process of transmitting to the access point an acceptance instruction of a terminal based on the correspondence relation according to sending of an emergency call, the acceptance instruction including information used for determining whether the access point allows connection with the terminal.

10. An access point, comprising:

a communication device configured to receive, from a server, information used for determining whether the access point allows connection with a terminal instead of a base station when an emergency call is sent; and

a controller configured to perform, when a connection request from the terminal is received, a connection process with the terminal under a condition that information included in the connection request is coincident with the information received from the server.

11. A terminal assignment method by a server, comprising:

the server storing, in a storage device, a correspondence relation between a terminal connected to a base station and an access point connectable with the terminal instead of the base station; and

the server executing a process of transmitting to the access point an acceptance instruction of a terminal based on the correspondence relation according to sending of an emergency call, the acceptance instruction including information used for determining whether the access point allows connection with the terminal.

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